A number of cast resinous objects have been produced which employ inert fillers dispersed throughout a thermosetting resin such as polyester. Known filler materials include calcium carbonate, glass fibers, asbestos, cinders, silicates, metal powders, quartz, clay, sand, alumina, volcanic ash, and the like.
There is a need for economic disposal of the by-products of a solids waste treatment plant for industrial or municipal garbage. In my co-pending application Ser. No. 201,111, a process is described for forming a valuable structural material using the incineration or pyrolysis residue of industrial or municipal solid waste products as a particulate reinforcement filler mixed with a resinous adhesive polymer binder which bonds the filler particles together. In my application Ser. No. 438,235, filed Jan. 31, 1974, a process described in which the fine waste residues of combustion processes are employed as particulate reinforcement filler when mixed with similar adhesive resinous polymer binders.
Another problem in a solids waste disposal system is the economic use of products of the so-called front-end system. As defined herein, such front-end resources recovery systems include any fraction from a municipal trash solids handling system which has been comminuted and classified but not pyrolyzed or incinerated. Such operations produce many different inorganic and combustible organic residues or rejects which are conventionally employed as land fill or directed to pyrolysis or incineration operations.
One reason why the shredded polymer-rich residue from a front-end system would form a poor material by itself is that it contains a number of mixed polymers which are incompatible with each other, for example, polyethylene and polyvinyl chloride. When these polymers are melt blended, the product appears striated or layered, is fibrillated and has inferior physical properties and poor structural integrity. When blends of these polymers are mixed without segregation, they have poor elongation properties and are cheesy and brittle.